1. Field of the Invention
The present invention generally relates to image decoding, and more particularly, to a method of decoding an image, an image decoder, and a mobile device including an image decoder.
2. Description of the Related Art
Modern mobile communication devices, such as cellular telephones, are commonly equipped with multimedia functionality. Examples including the playing of movies such as moving picture expert group (MPEG) files, the display of images such as joint picture expert group (JPEG) files, and the playing of audio files such as MPEG Layer 3 (MP3) files.
In the case of image files, such as JPEG files, it may be necessary to convert an original image file into a file which is suitable for display on the relatively small-sized display screen of the mobile device.
FIG. 1 is a diagram illustrating a process executed in a conventional mobile device to decode an original JPEG image to allow for display of the JPEG image on the screen of a mobile device.
The mobile device initially converts the original JPEG image 110 into a YUV image 120, and stores the YUV image in a YUV buffer memory. Generally, the size of the YUV image may be about twice that of the JPEG image. For example, if the size of the JPEG original image 110 is about 1.3 Megabytes, the size of the converted YUV image 120 may be about 2.6 Megabytes.
The mobile device then converts the YUV image 120 into an RGB image 130 (most display devices cannot directly display YUV formatted image data) which is stored in an RGB image buffer memory. For example, if the size of the YUV image 120 is about 2.6 Megabytes, the size of the converted RGB image 130 may be about 1.3 Megabytes.
The mobile device resizes the RGB image 130 into a final RGB image 140 that is suitable for the display screen of the mobile device. In the case of a liquid crystal display (LCD), the final RGB image 140 is stored in an LCD buffer memory. For example, the size of a final RGB image 140 suitable for display on the display device of the mobile device may be about 2.8 Kilobytes. In that case, an RGB image 130 of about 1.3 Megabytes, for example, would be converted into a final RGB image 140 of about 2.8 Kilobytes.
As is apparent from the above, substantial memory resources (e.g., the high capacity YUV buffer memory) are required to convert the JPEG original image 110 into the final RGB image 140.